Can’t import products in WooCommerce (403 error)
This 403 error shows in Woo 3.4+ and might also show in other versions too. It’s not an error generated by the server, but rather within WooCommerce. Sometimes in PHP/WordPress a 403 is actually based on a 500 or other error, according to some developers.
Long story short, use a different import plugin and it will work fine: